Is it possible to read a microSD card (on a breakout) through the USB port on the arduino? or perhaps another USB port I could attach to the breakout? Basically, I would like to read data off the card with my laptop without having to go and remove it each time!

Is it possible to read a microSD card (on a breakout) through the USB port on the arduino?

From the PC, no. The SD card reader is not a separate piece of hardware that you can connect directly to.

You could program the Arduino to respond to serial commands that direct it to return data from/about the SD card. Then, you'd need to write an application on the PC that could send the relevant commands and react to the returned information.

Sounds easy, but not for a newbee Is is possible with a ethetnet shield?I have an Seeeduino stalker and i want to copy the log file from the SD card to my pc once a while.Does anyone know how i can do this easy?

An SD card uses an SPI interface. You can talk to it with any device that can handle SPI, like the arduino. So the arduino can talk to your card and then use that data for something. Like in the Lady Ada sound shield or in various graphics LCD shields.

However, SPI is not a protocol that the PC talks, things like card readers convert the USB protocol to SPI and back to USB so the PC can make sense of it.

So the arduino can talk to your card and then use that data for something.

The Arduino can also talk to the serial port. You could develop an application on the PC that would tell the Arduino to spool data from the SD card back to the PC, via the serial port. The PC application would then need to store the data spooled back.

It wouldn't be possible to connect directly with the sd card trough a separate usb cable hooked onto the sd shield?Not going trough Arduino, so the sd cards looks just like a normal card connected directly to the pc.

My problems is that I need to make a watertight enclosure and i need access to the sd card files.